public void refreshBegin(Dataset dataset) { String key = dataset.getDataverseName() + "." + dataset.getDatasetName(); ExternalDatasetAccessManager datasetAccessMgr = globalRegister.get(key); if (datasetAccessMgr == null) { datasetAccessMgr = globalRegister.put(key, new ExternalDatasetAccessManager()); } // aquire the correct lock datasetAccessMgr.refreshBegin(); }